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Abstract

Chain transfer constants to monomer have been measured by an emulsion copolymerization technique at 70⁰C. The effects of ammonium persulfate (I) and sodium dodecylphenoxybenzenedisulphonate (E) on the chain transfer mechanism in the emulsion copolymerization of acrylonitrile and butyl acrylate have been investigated. For the system with the emulsifier concentration ([E]) 7.32 . 10^-2 mol dm^-3 and the initiator concentration ([I]) 2.28 . 10^-2 mol dm^-3 (the concentrations related to water volume) the relative transfer constant to monomer is 5.7 . 10^-5 for acrylonitrile polymerization and 1.05 . 10^-4 for the polymerization of butyl acrylate. In the system with lower [E] 0.63 . 10^-2 mol dm^-3 and the same [I] as given above the relative transfer constant to monomer is 3.33 . 10^-5 for both acrylonitrile and butyl acrylate polymerizations. In the system with [E] 7.32 . 10^-2 mol dm^-3 and [I] 1.4 . 10^-2 mol dm^-3 the relative transfer constant to monomer is 1.02 . 10^-4 for aacrylonitrile and 1.25 . 10^-4 for butyl acrylate polymerizations.